This invention relates to phenolic amides and the use of the amides as stabilizers for polymers such as polyols and/or polyurethane foams.
The stabilization of polyalkylene polyether polyols and other polymeric materials with antioxidants or other stabilizers and the use of the stabilized polyols in the preparation of polyurethane foams to inhibit scorch are well known to those skilled in the art. Polyether polyols used in the manufacture of slabstock flexible urethane foam are typically stabilized with antioxidant packages consisting of phenolic and amine antioxidants and may also contain the synergist phenothiazine or a phosphate moiety.
Illustrating such stabilization are U.S. Pat. Nos. 3,567,664 and 3,637,865 which disclose polyurethane foams stabilized with a mixture of 2,6-di-tert-butyl-4-methyl phenol [butylated hydroxy toluene (BHT)] and p,p'-dialkyldiphenylamines.
BHT (2,6-di-t-butyl-4-methyl phenol) is the most common and widely used hindered phenolic stabilizer for polyolefins, styrenics, vinyls, and elastomers. However, there are problems associated with the use of BHT such as long term discoloration, high volatility, sublimation, and difficulty of use due to its solid form. Hindered 2,6-di-t-butyl phenolics with various larger aliphatic groups replacing the methyl group in the para-position of the BHT ring have succeeded in reducing volatility, but usually at the expense of a reduction of activity of the antioxidant, as the more substituted compounds contain relatively less of the hindered hydroxy groups which provide the stabilization activity of hindered phenolic stabilizers.